# Cordyceps

Cordyceps /ˈkɔːrdɪsɛps/ is a genus of ascomycete fungi (sac fungi) that includes over 260 species worldwide, many of which are parasitic. Diverse variants of cordyceps have had more than 1,500 years of use in Chinese medicine. Most Cordyceps species are endoparasitoids, parasitic mainly on insects and other arthropods (they are thus entomopathogenic fungi); a few are parasitic on other fungi.
The generic name Cordyceps is derived from the ancient Greek κορδύλη kordýlē, meaning "club", and the Latin -ceps, meaning "-headed". The genus has a worldwide distribution, with most of the known species being from Asia.

## Taxonomy

There are two recognized subgenera:
* Cordyceps subgen. Cordyceps Fr. 1818
* Cordyceps subgen. Cordylia Tul. & C. Tul. 1865
Cordyceps sensu stricto are the teleomorphs of several genera of anamorphic, entomopathogenic fungi such as Beauveria (Cordyceps bassiana), Septofusidium, and Lecanicillium.

### Splits

Cordyceps subgen. Epichloe was at one time a subgenus, but is now regarded as a separate genus, Epichloë.
Cordyceps subgen. Ophiocordyceps was at one time a subgenus defined by morphology. Nuclear DNA sampling done in 2007 shows that members, including "C. sinensis" and "C. unilateralis", as well as some others not placed in the subgenus, were distantly related to most of the remainder of species then placed in Cordyceps (e.g. the type species C. militaris). As a result, it became its own genus, absorbing new members.
The 2007 study also peeled off Metacordyceps (anamorph Metarhizium, Pochonia) and Elaphocordyceps. A number of species remain unclearly assigned and provisionally retained in Cordyceps sensu lato.

### Selected species

There are over 260 species recognised in the genus Cordyceps including the following species:
* Cordyceps caespitosa
* Cordyceps militaris
* Cordyceps sinclairii

## Biology

When Cordyceps attacks a host, the mycelium invades and eventually replaces the host tissue, while the elongated fruit body (ascocarp) may be cylindrical, branched, or of complex shape. The ascocarp bears many small, flask-shaped perithecia containing asci. These, in turn, contain thread-like ascospores, which usually break into fragments and are presumably infective.

## Research

Polysaccharide components and the nucleoside cordycepin isolated from C. militaris are under basic research, but more advanced clinical research has been limited and too low in quality to identify any therapeutic potential of cordyceps components.

## Uses

Along with Ophiocordyceps, Cordyceps has long been used in traditional Chinese medicine in the belief it can be used to treat diseases. There is no strong scientific evidence for such uses.

## Cultural representations

The video game series The Last of Us (2013–present) and its television adaptation present Cordyceps as a deadly threat to the human race, its parasitism powerful enough to result in global calamity. The result is a zombie apocalypse and the collapse of human civilization. Scientific American notes that some species in the genus "are indeed body snatchers–they have been making real zombies for millions of years", though of ants or tarantulas, not of humans. The Last of Us proceeds from the premise that a new species of Cordyceps manages to jump between species of host, just as diseases like influenza have done. Its human hosts initially become violent "infected" beings, before turning into blind zombie "clickers", complete with fungal "fruiting bodies sprouting from their faces". In an additional detail that reflects Cordyceps biology, "clickers" then seek out a dark place in which to die and release the fungal spores, enabling the parasite to complete its life cycle. Scientific American comments that by combining a plausible mechanism with effective artistic design, the series gains "both scientific rigor and beauty".
In similar vein, Cordyceps causes a pandemic that wipes out most of humanity in Mike Carey's 2014 postapocalyptic novel The Girl with All the Gifts and its 2016 film adaptation. In this case, an infected person becomes a "hungry", a zombie thirsting for blood. In the fiction, Dr. Caldwell explains that the human-infecting fungus is a mutated form of Ophiocordyceps unilateralis (a group of species now split off from Cordyceps) which alters the behaviour of infected insects. The children of infected mothers, however, become "hybrids" with antibodies protecting them against the fungus.

## Gallery

* Cordyceps beginning its fruiting growth from a wasp
* Cordyceps militaris
* Cordyceps militaris
* Cordyceps ophioglossoides